Pesticides linked to breast cancer

Chemicals in the environment that act like human hormones could be the cause of 'an unexplained increase in breast cancer', says Devra Lee Davis, a toxicologist and senior adviser to the US Assistant Secretary for Health. Chemicals should be screened for their ability to mimic the hormone oestrogen before they are released into the environment, she says.

Oestrogen has long been linked to breast cancer through epidemiological data, which relates a woman's risk to her estimated exposure to the hormone, and through the finding that oestrogen stimulates cells in the breast to multiply rapidly. Now some scientists are claiming that extra doses of oestrogen-like compounds in the environment may increase the quantities of hormone some women receive to dangerous levels.